Fix incorrect processing of VerificationFreq parameter #2740
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| @@ -397,7 +397,7 @@ func (bsm *BroadcastSessionsManager) shouldSkipVerification(sessions []*Broadcas | |||
| if !includesSession(sessions, bsm.verifiedSession) { | |||
| return false | |||
| } | |||
| return common.RandomUintUnder(bsm.VerificationFreq) == 0 | |||
| return common.RandomUintUnder(bsm.VerificationFreq) != 0 | |||
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Ooof good catch!
IIUC this method generates a random integer x s.t. 0 <= x < VerificationFreq and there would be a 1 / VerificationFreq probability for the random integer to be 0. Since this method is checking if verification should be skipped, if the check on this line is whether the integer is equal to 0 then this method would return true 1 / VerificationFreq of the time which is the opposite of what we want i.e. this method should return true (VericationFreq - 1) / VerificationFreq) of the time.
Codecov Report
@@ Coverage Diff @@
## master #2740 +/- ##
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Coverage 56.34825% 56.34825%
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Files 88 88
Lines 19147 19147
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Hits 10789 10789
Misses 7767 7767
Partials 591 591
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* fix semantics of shouldSkipVerification * go fmt * Fix test to align with the meaning of verificationFreq parameter
About
VerificationFreqparameter of the transcoding job controls how often fast verification is re-run on an already verified O session. Fast verification involves transcoding segment with 1 trusted and 2 untrusted Os, instead of using a single O. This PR fixes incorrect processing of this parameter. Valid values are 0 and positive integers. IfVerificationFreq = 0, fast verification logic is fully disabled. IfVerificationFreq=N>0, then, after initial verification run for a new O session, it will run again for a segment with a probability of1 / VerificationFreq.Issue
The
shouldSkipVerificationfunction usedVerificationFreqparameter in an inverted way.VerificationFreq=1caused fast verification to run only once, as long as verified session is available, and higher values caused fast verification to run more and more often, with a value of e.g. 40 giving a 97.5% chance of running fast verification for each new segment of the stream.